Kaur Gurpreet, Rawat Nisha, Ravikanth Mangalampalli
Indian Institute of Technology, Powai, Mumbai 400076, India.
J Org Chem. 2023 Nov 3;88(21):14989-14997. doi: 10.1021/acs.joc.3c01448. Epub 2023 Oct 25.
A new type of expanded dibenzothiophene-containing thiacarbaporphyrinoid containing one dibenzothiophene, two -phenylene, one thiophene, and two pyrrole rings connected via four carbons and two direct bonds was synthesized over a sequence of six steps starting with commercially available dibenzothiophene. The X-ray structure obtained for one of the macrocycles revealed that the macrocycle was very nonplanar and the two -phenylene rings and dibenzothiophene unit were deviated from the mean plane, whereas the thiophene ring attained inverted conformation and was facing toward outside the macrocyclic core. The X-ray structure also revealed that the dibenzothiophene unit of the macrocycle maintained its π-electron delocalization and did not extend the π-electron delocalization with the rest of the macrocycle, and the effective π-conjugation was present only in the lower part of the macrocyclic core, i.e., the thiatripyrrin moiety. The spectral and theoretical studies support the nonaromatic nature of the macrocycles. The macrocycles exhibit one strong absorption band at ∼430 nm and one broad absorption band in the 500-800 nm region, which were bathochromically shifted in diprotonated derivatives which absorb strongly in the visible-NIR region. The electrochemical studies indicated the electron-rich nature of the macrocycles and the theoretical studies corroborated the experimental observations.
以市售的二苯并噻吩为起始原料，通过六个步骤合成了一种新型的含二苯并噻吩的扩展硫代碳卟啉类化合物，该化合物含有一个二苯并噻吩、两个亚苯基、一个噻吩和两个吡咯环，通过四个碳原子和两个直接键相连。对其中一个大环化合物进行X射线结构分析发现，该大环化合物非常非平面，两个亚苯基环和二苯并噻吩单元偏离平均平面，而噻吩环呈反式构象并朝向大环核心外部。X射线结构还表明，大环化合物的二苯并噻吩单元保持其π电子离域，且不与大环的其余部分扩展π电子离域，有效的π共轭仅存在于大环核心的下部，即硫代三吡咯部分。光谱和理论研究支持了大环化合物的非芳香性质。大环化合物在约430 nm处呈现一个强吸收带，在500 - 800 nm区域呈现一个宽吸收带，在二质子化衍生物中这些吸收带发生红移，在可见 - 近红外区域有强烈吸收。电化学研究表明大环化合物具有富电子性质，理论研究证实了实验观察结果。
